Field
This invention relates generally to voltage-to-current converters, and more specifically, to voltage-to-current converters configured to minimize current and output voltage reference error.
Background
Low-noise, low-power, wideband, and high-resolution digital-to-analog converters (DACs) are important for advanced wireless standards such as long term evolution (LTE). To support output power control of a power amplifier (PA), the full scale current of the DAC is required to be tuned from −18 dB to 0 dB with 1 dB/step accuracy. To achieve this precise current requirement for the DAC, a voltage-to-current converter in the DAC needs to be very stable and precise. However, the output voltage and current of a conventional voltage-to-current converter typically show large variations as well as inaccuracies due to the on-resistance variation across process-voltage-temperature (PVT) and the leakage current of switches in the voltage-to-current converter. This causes the output full current calibration of the DAC to be inaccurate and limits the DAC performance.